Forum Moderators: coopster
I am calling images using php (e.g. http://www.example.com/wp-content/?img=p85-100x100.jpg ) then a small PHP script will either return 404 (not found), 200 (OK) or 304 (not modified)
Script works well on local machine as I get a 304 after refreshing page but on server I always get a 200.
On localhost I get this
[b]Response Headers[/b]
Date Tue, 13 Oct 2009 14:29:29 GMT
Server Apache/2.2.9 (Win32) DAV/2 mod_ssl/2.2.9 OpenSSL/0.9.8i mod_autoindex_color PHP/5.2.6
X-Powered-By PHP/5.2.6
Content-Length 3820
Expires Wed, 13 Oct 2010 14:29:22 GMT
Accept-Encoding gzip, deflate
Cache-Control public, max-age=31536000, s-maxage=31536000
Last-Modified Fri, 17 Apr 2009 08:56:45 GMT
Etag b894c26a6053bc42f738a84c74116848
Content-Encoding gzip
Vary Accept-Encoding
Content-Type image/jpeg
Content-Language en-IS
[b]Request Headers[/b]
Host localhost
User-Agent Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.9.0.14) Gecko/2009082707 Firefox/3.0.14
Accept text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language en-gb,en;q=0.5
Accept-Encoding gzip,deflate
Accept-Charset ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive 300
Connection keep-alive
If-Modified-Since Fri, 17 Apr 2009 08:56:45 GMT
If-None-Match b894c26a6053bc42f738a84c74116848
Cache-Control max-age=0
On server I get this
[b]Response Headers[/b]
Date Tue, 13 Oct 2009 14:28:50 GMT
Server Apache/2.2.11 (Unix) mod_ssl/2.2.11 OpenSSL/0.9.8i DAV/2 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635
X-Powered-By PHP/5.2.9
Expires Wed, 13 Oct 2010 14:29:14 GMT
Accept-Encoding gzip, deflate
Cache-Control public, max-age=31536000, s-maxage=31536000
Etag b894c26a6053bc42f738a84c74116848
Content-Encoding gzip
Vary Accept-Encoding
Content-Length 3959
Last-Modified Wed, 07 Oct 2009 19:05:35 GMT
Content-Type image/jpeg
Content-Language en-IS
Proxy-Connection keep-alive
[b]Request Headers[/b]
Host www.example.com
User-Agent Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.9.0.14) Gecko/2009082707 Firefox/3.0.14
Accept text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language en-gb,en;q=0.5
Accept-Encoding gzip,deflate
Accept-Charset ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive 300
Proxy-Connection keep-alive
As you can see, the request header on server doesn't have a If-Modified-Since and If-None-Match when calling photos/?img=img_name.jpg. However, it is there when calling directly photos/img_name.jpg. Any idea why ?
And my PHP script is actually using these
if ((isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) && strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE'])==$last_modified_time) ¦¦ (isset($_SERVER['HTTP_IF_NONE_MATCH']) && trim($_SERVER['HTTP_IF_NONE_MATCH'])==$etag)) {
header("HTTP/1.1 304 Not Modified");
exit();
} else {
header("Content-type: ".$mime);
header("Content-length: ".filesize($img_path));
header("Expires: ".gmdate("D, d M Y H:i:s", time() + $offset)." GMT");
header("Accept-Encoding: gzip, deflate");
header("Cache-Control: public, max-age=".$offset.", s-maxage=".$offset."");
header("Last-Modified: ".gmdate("D, d M Y H:i:s", $last_modified_time)." GMT");
header("ETag: ".$etag);
$fn = @fopen("./".$img, "r");
if($fn) {fpassthru($fn);}
exit();
}
Your help would be greatly appreciated
As you can see above, response header from my server really sucks (no expires date, no gzip compression - only etags is returned).
www.example.com/photo/test.jpg
DateWed, 14 Oct 2009 10:17:55 GMT
ServerApache/2.2.11 (Unix) mod_ssl/2.2.11 OpenSSL/0.9.8i DAV/2 mod_auth_passthrough/2.1 mod_bwlimited/1.4 FrontPage/5.0.2.2635
Last-ModifiedWed, 07 Oct 2009 12:42:09 GMT
Etag"5b74223-a3fd-47557ae41e040"
Accept-Rangesbytes
Content-Length41981
Content-Typeimage/jpeg
Content-Languageen-IS
X-CacheMISS from proxy2.unon.org
Via1.0 proxy2.unon.org:3128 (squid/2.6.STABLE12)Since I don't have mod_headers (shared server), I am just trying to call the images throught PHP $_GET variable using the script above (see extract - set far expire date, etags and gzip content).
www.example.com/photo/?img=test.jpg
MAIN ISSUE - $_SERVER['HTTP_IF_MODIFIED_SINCE'] and $_SERVER['HTTP_IF_NONE_MATCH'] doesn't exist ! And I have no idea why ?
MY SOLUTION - Using curl to get HTTP response header data and fetch Last-Modified and Etags from response header => working on it now, almost done need to finalise regex to extract data
BEST SOLUTION - Using curl to get HTTP request header data.
*************
I have three questions:
A/ Is this method dumb ? From previous discussion I had on WW forum, this method is the only one acceptable when mod_headers is not available; anyone using it ? Please share your experience.
B/ Can I fetch REQUEST header data using Curl (I am only able to get RESPONSE header currently) ?
C/ Strangely, it seems that my pages load much faster when calling images directly (at first load). I am afraid that my PHP script + curl will use too much CPU resources and make things worst (knowing that I have appr. 30 images per pages)
Thanks
